BRACHIOPODA. 
11 
scars. The same may be said of the other scars, all of which show something of this 
progressive increase in size. The impressions which appear to be most gener¬ 
ally retained among the fossils are the anterior laterals (j) of the brachial valve, 
and the middle laterals ( k ) of the pedicle-valve. These lie in the ante-median 
portion of the valves, and, in their progress forward, have left long, conspicu¬ 
ous tracks which follow the axis of the shell. 
The separate members of these pairs of impressions are not always, or even 
often, to be distinguished, the long axial impression accompanied by the ante¬ 
rior portions of the broad centrals being usually all that is visible of the mus¬ 
cular scars. The subdivision and asymmetry of these scars in L. anatina has 
been determined only by the aid of the attached muscular bands. Without their 
assistance it would prove difficult, if not impracticable, to ascertain their exact 
limitations, merely from the impressions upon the shells. This will, to a certain 
degree, be made evident by comparing Professor King’s figures with those of 
the same species given on Plate I ; in the latter drawings the scars have been 
somewhat emphasized, but it is impossible to resolve, with any degree of 
accuracy, the compound lateral and transmedian scars ( k , l, i, in the brachial, j, i, 
in the pedicle-valve). Nevertheless, in the brachial valve of L. Whitii, the com¬ 
pound lateral scar is quite distinct, and the umbonal (g) impression well defined. 
On the brachial valve of L. Elderi , Mr. Whitfield has shown the former to be 
even more clearly defined than in L. Whitii, and the umbonal scar to be un¬ 
usually large. In both these species, the laterals and transmedians are situated 
considerably nearer the umbonal region than in L. anatina. The pedicle-valve 
of L. Elderi shows the transmedian scars, which are represented as two on each 
side, the anterior of which is regarded by the author as the scar of the 
“posterior adjustors” (transmedian) and “anterior adductors” combined. 
Lingula punctata shows comparatively broad muscular scars in this region, but 
it has been impossible to resolve them satisfactorily. The umbonal scar also, 
appears on the pedicle-valve of L. Elderi. 
A species of Lingula from the Cuyahoga shale at Johnstown, Chardon, and 
elsewhere in Ohio, which has usually been confounded with the common L. Melie 
